from sys import argv

script, file_name = argv

def print_all(f):
  print f.read()
  
def rewind(f):
  f.seek(0)
  
def print_a_line(line_cnt, f):
  print line_cnt, f.readline()
  
current_file = open(file_name)
print "First let's print the whole file:\n"
print_all(current_file)

print "Now let's rewind, kind of like a tape."
rewind(current_file)

print "Let's print three lines:"
current_line = 1
print_a_line(current_line, current_file)
current_line +=1
print_a_line(current_line, current_file)
current_line +=1
print_a_line(current_line, current_file)